The use of objects molded from synthetic polymers has expanded rapidly in the last several decades. In particular, polyesters and polyamides have widely gained acceptance for general molding applications and in the formation of fibers and films. An additional class of polymers known as poly(esteramides) has been disclosed. Such disclosures include U.S. Pat. Nos. 2,547,113; 2,946,769; 3,272,774; 3,272,776; 3,440,218; 3,475,385; 3,538,058; 3,546,178; 3,575,928; 3,676,291; 3,865,792; 3,926,923; and 4,116,943. Polyimide esters are disclosed in German Offenlegungsschrift No. 2,950,939 and in U.S. Pat. No. 4,176,223.
Although many polyesters, polyamides, and poly(esteramides) have mechanical properties suitable for general applications, most polyesters, polyamides, and poly(ester-amides) are not suitable for high strength service because the mechanical properties are not sufficiently high. One group of polymers that is suitable for high strength service without the use of a reinforcing agent is a new class of polymers exhibiting a general overall balance of mechanical properties substantially enhanced over previous polymers. These polymers have been described by various terms, including "liquid crystalline", "liquid crystal", and "anisotropic". Briefly, the polymers of this new class are thought to involve a parallel ordering of the molecular chains. The state wherein the molecules are so ordered is often referred to either as the liquid crystal state or the nematic phase of the liquid crystal state. These polymers are prepared from monomers which are generally long, flat, and fairly rigid along the long axis of the molecule and commonly have chain extending linkages that are either coaxial or parallel.
Disclosures of polyesters which exhibit melt anisotropy include (a) Polyester X7G-A Self Reinforced Thermoplastic, by W. J. Jackson Jr., H. F. Kuhfuss, and T. F. Gray, Jr., 30th Anniversary Technical Conference, 1975 Reinforced Plastics/Composites Institute, The Society of the Plastics Industry, Inc., Section 17-D, Pages 1 to 4, (b) Belgian Pat. Nos. 828,935 and 828,936, (c) Dutch Pat. No. 7505551, (d) West German Pat. Nos. 2520819, 2520820, 2722120, 2834535, 2834536, and 2834537, (e) Japanese Pat. Nos. 43-223; 2132-116; 3017-692; and 3021-239, (f) U.S. Pat. Nos. 3,991,013; 3,991,014; 4,057,597; 4,066,620; 4,067,852; 4,075,262; 4,083,829; 4,118,372; 4,130,545; 4,130,702; 4,156,070; 4,159,365; 4,161,470; 4,169,933; 4,181,792; and 4,184,996; and (b) U.K. Application No. 2,002,404. See also commonly assigned U.S. Ser. Nos. 10,392, filed Feb. 8, 1979; (now U.S. Pat. No. 4,238,599) 10,393, filed Feb. 8, 1979; (now U.S. Pat. No. 4,238,598) 32,086, filed Apr. 23, 1979; (now U.S. Pat. No. 4,219,461) and 54,049, filed July 2, 1979 (now U.S. Pat. No. 4,256,624).
Disclosures of liquid crystalline polyamide dopes include U.S. Pat. Nos. 3,673,143; 3,748,299; 3,767,756; 3,801,528; 3,804,791; 3,817,941; 3,819,587; 3,827,998; 3,836,498, 4,016,236; 4,018,735; 4,148,774; and Re.30,352.
U.S. Pat. No. 4,182,842 discloses poly(ester-amides) prepared from an aromatic dicarboxylic acid, ethylene glycol, and a p-acylaminobenzoic acid. This patent neither discloses nor suggests the poly(ester-amide) of the present invention. A similar disclosure is Japan 54 125271.
European Patent Application No. 79301276.6 (Publication No. 0 007 715) discloses melt processable fiber-forming poly(ester-amides) comprising residues of one or more aminophenols selected from p-aminophenol and p-N-methylaminophenol and residues of one or more dicarboxylic acids. The poly(ester-amide) contains a balance of linear difunctional residues and dissymmetric difunctional residues derived from either the aminophenols or the acids. The linear difunctional residues and dissymmetric difunctional residues are chosen so as to give a product which melts below its decomposition temperature and exhibits optical anisotropy in the melt. This patent neither discloses nor suggests the poly(ester-amide) of the present invention which contains a 6-oxy-2-naphthoyl moiety.
U.S. Pat. No. 3,859,251 discloses a poly(ester-amide) which comprises 50 to 100 mole percent of the moiety derived from an acyclic aliphatic dicarboxylic acid. Such a moiety is excluded from the poly(ester-amide) of the present invention. Moreover, while the patent discloses the inclusion of a p-oxybenzoyl moiety, there is no disclosure nor suggestion of the usefulness of a poly(ester-amide) containing a 6-oxy-2-naphthoyl moiety, such as that of the present invention.
U.S. Pat. No. 3,809,679 discloses poly(ester-amides) consisting of 10 to 90 mole percent of recurring structural units derived from a dicarboxylic acid dihalide and a dihydroxy compound of a specified formula and 10 to 90 mole percent of recurring structual units derived from a dicarboxylic acid dihalide and a diamino compound of a specified formula. The poly(ester-amides) specifically exclude moieties derived from aromatic hydroxyacids, such as the 6-oxy-2-naphthoyl moiety included in the poly(ester-amide) of the present invention. Furthermore, most, if not all, of the poly(ester-amides) disclosed are not readily melt processable, and there is no disclosure of the existence of an anisotropic melt phase.
Therefore, it is an object of the present invention to provide an improved poly(ester-amide) which is suited for the formation of quality molded articles, melt extruded fibers, and melt extruded films.
It is also an object of the present invention to provide an improved poly(ester-amide) which forms a highly tractable melt phase.
It is also an object of the present invention to provide an improved poly(ester-amide) which forms an anisotropic melt phase at a temperature well below its decomposition temperature and which may form quality fibers, films, and molded articles.
It is also an object of the present invention to provide an improved melt processable poly(ester-amide) capable of forming an anisotropic melt phase at a temperature below approximately 400.degree. C., and preferably below approximately 350.degree. C.
It is also an object of the present invention to provide an improved melt processable poly(ester-amide) which exhibits improved adhesion, improved fatigue resistance, and increased transverse strength.
These and other objects, as well as the scope, nature, and utilization of the present invention, will be apparent to those skilled in the art from the following detailed description.